Harden CI token permissions and clarify iOS target note

Agent-Logs-Url: https://github.com/fabiocaccamo/FCFileManager/sessions/3cc3f882-393c-4a34-b716-5d88ba506d3d

Co-authored-by: fabiocaccamo <1035294+fabiocaccamo@users.noreply.github.com>

Author: Copilot

.github/workflows/ci.yml

@@ -5,6 +5,9 @@ on:
     branches: ["**"]
   pull_request:
 
+permissions:
+  contents: read
+
 jobs:
   tests:
     runs-on: macos-latest

README.md

@@ -16,6 +16,8 @@ This repository now includes an XCTest suite runnable with Xcode's Swift Package
 xcodebuild test -scheme FCFileManager-Package -destination "platform=iOS Simulator,name=iPhone 16"
 ```
 
+Note: the Swift Package test harness currently targets iOS 13+ (see `Package.swift`), while the CocoaPods distribution keeps the original minimum deployment target (iOS 5.0).
+
 ### Continuous Integration
 A GitHub Actions workflow is available at `.github/workflows/ci.yml` and runs the test suite on each push and pull request.